BAD MPG, FPR not problem

[everydayrider99]

Just trying to keep it short. I have done my reading on the site. I know enough about the FPR problem to know something else must be wrong, and wouldnt mind some opinions. About 3000 miles ago, my bike got shitty MPG, read up on it, and ended up changing out the broken FPR on my 99 to one from an 02 for the higher pressure. This worked for awhile. I ran some seafoam through, as this bike I bought had sat awhile. The bike continued to work fine. Miles per tank nearly 200. For some reason the gas mileage got shitty again after about 3000 miles. I changed the FPR to the model year 99 OEM. And the gas mileage still sucks. The bikes smells like gas, and there is gas in the oil again. Cant be the FPR.... suggestions? I also just changed out my SS2R slip ons back to the stock pipes for commuting.

[Warp11XX]

Never say never. If the FPR's weren't brand new from Honduh, they could potentially still be part of the problem. Checked the obvious stuff I would guess....fuel lines, injector bodies and seals, etc. Haven't heard of ECU problems, but couldn't hurt to try a swap if you had one available. I keep coming back to the "gas in the oil" part of your diagnostics....FPR is almost the only culprit there...

Good luck and let us know what works ultimately.

[spicholy]

Are you running a power commander with mapping for the aftermarket cans? If so, did the map richen the mixture at all? If so, the stock cans may restrict the flow causing an overly rich situation. That's all I got.

BTW, my '99 sometimes has a smell of gas. I usually get in the low 30 mpg range of mixed riding. I do have a tough time of keeping my wrist from twisting too quickly though.

[tomek]

Check the vacuum lines at the throttle bodies or better yet get new ones . Get couple feet of vacuum hose from Autozone and replace them piece by piece .

BTW , if 02 FPR has indeed higher pressure it would reduce your mpg .

FPR on XX is a reference type or maintains constant pressure in the fuel rail in relation to the intake manifold , if engine is under less then full load ( vacuum ) it drops pressure accordingly .

Example.

If the vacuum is 5 psi FPR will lower the pressure by 5 psi , let`s say from 45 psi to 40 . What matters is the delta between fuel rail and the manifold because that`s were the tips of injectors are .

Now , if one of the vacuum lines is broken FPR only sees atmospheric pressure , so under light loads you are ending up with unnecessarily rich mixtures due to FPR not lowering pressure . Higher pressure in the fuel rail , more flow in the given time , richer mixtures .

[EVLXX]

Check the vacuum lines , if one of the vacuum lines is broken, you are ending up with unnecessarily rich mixtures, Because of Higher pressure in the fuel rail.

+1

[everydayrider99]

I am guessing you are talking about the vacuum line coming from the FPR, mine does look a little rough. Are you saying, if this is cracked or broken, it cannot detect pressure? Would you go into more detail about this?

[tomek]

FPR adjusts ( lowers) pressure based on the vacuum readings in that line . If you look closely you`ll see it is connected via couple Ts to vacuum lines coming out from intake manifolds for each cylinder .

If any of them is cracked or broken the end result could be "higher" pressure in the fuel rail leading to mpg drop .

On 10 plus years old bike I would not bother with checking each and every line . I suggest getting some bulk vacuum line of correct I.D ( 3 , maybe 5mm , I don`t remember) from auto parts story and replacing them piece by piece . Remove old one , cut new one to the correct length , etc .

That way you won`t have to worry about / waste time figuring out what goes where later .

[everydayrider99]

Sounds simple enough, thanks man.

[everydayrider99]

Alright, guru's, bullshitters, techy's or whomever else may give a shit.

2 months after starting this thread I finally got off my ass and did something about it. Friday I replaced the chain and sprockets, same stock gearing as before, and cleaned the shit out of everything in there. Oil/filter change, bleed clutch, and replaced all vacuum tubes. Should have done brake fluid, oh well. Checked the free spin on both tires, bearings and brakes seem good. Bike feels brand new.

Same gas mileage, shitty. When I bought the bike, the owner had just changed the spark plugs he said. Yea, raised my suspicions also, but got a good price so fuck it. I soon find out my FPR is shit, and replaced it. When I first replaced it, gas milage seemed a bit better for awhile, then became shitty again, tried another FPR, no bueno. I ride fairly hard, but recently toned it down a bit to see if there was a fluctuation in MPG, barely.

?

Enough BS'ing. Next steps... air filter change? another spark plug change? vac sensor? Quit bitching?

Thanks

Dan

[EVLXX]

Alright, guru's, bullshitters, techy's or whomever else may give a shit.

?

Enough BS'ing. Next steps... air filter change? another spark plug change? vac sensor? Quit bitching?

Thanks

Dan

Really?

All this time and you haven't checked the air cleaner yet ?

How about the PAIR unit, is it still on the bike?

And all the components to your MAP sensor are good?

...

You do realize we are all trying to make sure the simple easy to repair basics are covered.... because once you get that out of the way, then we move on to injectors.

[The Krypt Keeper]

Check plugs, did the correct plugs go in from PO? irridium plugs don't need to be gapped

Airfilter either a honda filter or a k&N, both nice and clean.. Mice love airboxes to build nest if bike left to sit.

Bleed your brake system, might be slightly dragging a brake. (there is a how to write on it. LBS systems are fun) just because your wheels spin freely in air doesn't mean once things warm up your brakes they grab some.

[Hobicus]

Good suggestions so far:

Double check the vaccuum lines, although the bike will feel different, especially off/on throttle when those are not working. Been there, done that.

IF the FPR was causing it to run rich, it's possible that one of the plugs fouled. It's also possible that the guy used cheap plugs when he replaced them (or attempted to gap them, destroying the iridium tips), causing them to wear out quickly.

[redxxrdr]

I battled the same problem last year. A new FPR and replacing all vaccuum lines brought me up from 26 mpg back into the mid 30's.

But, I have never gotten back to the 220 mile before low fuel warning that I had when new.

I think it's the gas. Or the corn oil crap that I have to buy now.

My new fleet van had a mileage per tank table printed on the window. It literally showed a 25 % difference with ethanhol base fuels.

There are web sites that show stations in my area with good old Dino fuel. I have run a tank of the straight stuff and have seen the mileage go up. Those fuels don't cost much more. I would try a couple of tanks just to make sure that your bike isn't giving you all it can for the EPA

[everydayrider99]

Air filter and plugs this weekend. I think the bike may have sat awhile in some sort of outdoor environment, shed, outside covered, who knows.

My VFR sat in a horse stable for 3 months, covered, and wrapped in a tarp. I removed the battery and some little shit head mouse made a nest where my battery should have been.

Thanks for the advice

[EVLXX]

I battled the same problem last year. A new FPR and replacing all vaccuum lines brought me up from 26 mpg back into the mid 30's.

But, I have never gotten back to the 220 mile before low fuel warning that I had when new.

I think it's the gas. Or the corn oil crap that I have to buy now.

My new fleet van had a mileage per tank table printed on the window. It literally showed a 25 % difference with ethanhol base fuels.

There are web sites that show stations in my area with good old Dino fuel. I have run a tank of the straight stuff and have seen the mileage go up. Those fuels don't cost much more. I would try a couple of tanks just to make sure that your bike isn't giving you all it can for the EPA

For the first year of my bikes life... I believe the best mpg I got was 34. Then somewhere along the lines I got a Power Commander, and have never been the same since, but it took the power commander to break above 36 for sure.

As for the Ethanol laden fuel.... I Fucking Hate it... but... it's all I can buy. On our pumps there is a sticker that says... "May contain up too 10%"... the key word there is "May".. Since it's not easy to figure out how much ethanol is in your fuel, figuring out the exact amount of MPG loss that can be expected is nearly impossible. The only way you can get close.. is if you have been diligent about recording your mileage for years prior to the introduction of the crappy fuel in your area.

Here... I can tell you that you will see a reduction in fuel efficiencies from .. 7% all the way up to 15%, dependent upon which station you consistently fill up at.. due soulfully to the ethanol percentage and fuel quality content.

[jon haney]

One more thing you could check. Engine temperature sensor. If your bike is like mine, and runs at the bottom of the "normal range" most of the time, the ECU will add a little extra fuel. I've been tempted to change the sensor or try to find a thermostat with a higher opening temp, if there is one.

Best mileage I ever made was in Colorado during the West Coast Bash at Montrose. Warning light came on at about 185 miles (usually comes on about 145-150 for highway trips). We were "hauling ass" for most of those miles, so I was freaking out that no one was stopping for gas. Not a lot of places to fill-up out there. Double freak out for going 198 miles on a single tank at those speeds.

Good luck.

[slowrideCX]

On the FI bikes if you are not running up to temp the computer is trying to richen the mixture as it would do in the winter for a cold start. If it runs like that all the time you will have the low miles you are having..

[everydayrider99]

Well yes this temperature issue interesting... never heard of anything like it.

On the highway, my indicator is almost at C. Which I thought was a good thing, that the bike runs cool, rather than hot. I know too cold sucks.. but mid to low good?

[The Krypt Keeper]

I got a digital temp gauge but I normally run around 185 - 190 at highway speed in clean air.

In ball sweating summer heat might be around 190 - 195 at highway speed in clean air.

I was actually impressed with my fuel consumption going to WVXXT a couple weeks ago. Cruising at 80 -83mph indicated and then hauling ass up a mountain and got 43.5mpg. Normally get about 40mpg or less.

Worse to date for me was around 28mph +/- .. but I know why.

[slowrideCX]

Well yes this temperature issue interesting... never heard of anything like it.

On the highway, my indicator is almost at C. Which I thought was a good thing, that the bike runs cool, rather than hot. I know too cold sucks.. but mid to low good?

The temp is not so much an issue on a carbed bike with a manual choke/enrichener but on the FI bikes the computer controls the mixture according to air temp motor temp oxygen level in the exhaust yadda yadda too many variables to list. Bottom line is if the motor is not running about 180-190 the computer will think it is still trying to warm the engine and keep richening the mixture.

Could be as mentioned before temp sensor or thermostat.

Good luck.

[CBRXX]

My '02 will run at 180 when it is nice and cool and rolling steady on highway. Sometime will even dip to 178.

Gas mileage is usually above 35mpg, sometimes see 40.

[ptxyz]

i've been following this thread with interest since i've always had crappy mileage with my 2000. usually around 25 mpg for my commute (i have a very heavy throttle hand...). i've measured (re-set trip meter when filling the tank to full - i know, only somewhat accurate) as high as low 40's on a sedate group ride. the bike tends to smell rich, even after fully warmed. the ends of the stock cans get black pretty soon after cleaning. except for comfort items (corbin & givi tail box), all stock.

the temp tends to run towards the middle of the range with the fan coming on when moving slowly. she's definitely warmer than my previous bird.

i intend to get the tank off (much more involved than my previous '97) to have a closer look at the vaccum lines and air cleaner.

couple questions; is my fuel economy within what others experience? is there a way to test the fpr? i see new ones around $50 on the web.

thanks in advance for the input!

[RXX]

I battled the same problem last year. A new FPR and replacing all vaccuum lines brought me up from 26 mpg back into the mid 30's.

But, I have never gotten back to the 220 mile before low fuel warning that I had when new.

I think it's the gas. Or the corn oil crap that I have to buy now.

My new fleet van had a mileage per tank table printed on the window. It literally showed a 25 % difference with ethanhol base fuels.

There are web sites that show stations in my area with good old Dino fuel. I have run a tank of the straight stuff and have seen the mileage go up. Those fuels don't cost much more. I would try a couple of tanks just to make sure that your bike isn't giving you all it can for the EPA

For the first year of my bikes life... I believe the best mpg I got was 34. Then somewhere along the lines I got a Power Commander, and have never been the same since, but it took the power commander to break above 36 for sure.

As for the Ethanol laden fuel.... I Fucking Hate it... but... it's all I can buy. On our pumps there is a sticker that says... "May contain up too 10%"... the key word there is "May".. Since it's not easy to figure out how much ethanol is in your fuel, figuring out the exact amount of MPG loss that can be expected is nearly impossible. The only way you can get close.. is if you have been diligent about recording your mileage for years prior to the introduction of the crappy fuel in your area.

Here... I can tell you that you will see a reduction in fuel efficiencies from .. 7% all the way up to 15%, dependent upon which station you consistently fill up at.. due soulfully to the ethanol percentage and fuel quality content.

Do you live near any of these places??

http://pure-gas.org/index.jsp?stateprov=CO

[JoWhee]

i've been following this thread with interest since i've always had crappy mileage with my 2000. usually around 25 mpg for my commute (i have a very heavy throttle hand...). i've measured (re-set trip meter when filling the tank to full - i know, only somewhat accurate) as high as low 40's on a sedate group ride. the bike tends to smell rich, even after fully warmed. the ends of the stock cans get black pretty soon after cleaning. except for comfort items (corbin & givi tail box), all stock.

the temp tends to run towards the middle of the range with the fan coming on when moving slowly. she's definitely warmer than my previous bird.

i intend to get the tank off (much more involved than my previous '97) to have a closer look at the vaccum lines and air cleaner.

couple questions; is my fuel economy within what others experience? is there a way to test the fpr? i see new ones around $50 on the web.

thanks in advance for the input!

I was lucky to get 200km/ 120 miles from fillup to reserve light on my '00 A power commander with the stock map gives me another 60km ~40 miles from full to res light. Just looking at the PC map I noticed that the one from dynojet pulls out quite a bit of fuel in the mid range, compared to stock. I had done pretty much everything else first to track down the poor mileage (compared to my '97). Air filter, vac lines, temp sensor FPR, I had even swapped out the ECU. About the only thing I didn't try was the Baro sensor at the back of the bike, it's placement looks less than ideal to me. I was getting the rich smell and the sooty exhaust also. Between here and the .com forum, it seems the nature of the 99-00 bikes to run rich.

[everydayrider99]

I cant update yet... switched out the air filter and plugs today. Actually much easier than I expected. Anyway, when I got everything back together, I lifted the tank slightly, peaked in, started the bike, and gas started spraying a nice costly mist out of the fuel feed hose. This was not the problem to begin with, I have looked under the tank while it was running plenty of times recently. All of the moving around the tank and what not must have cracked it, it looks pretty dried out. At least I am learning quite a bit about my bike with all the part swaps.

Any easy fixes for the hose? Or just order a new one for 69.95 from an online site? 69.95 for 4 ounces of steel and some rubber, nice.